import Vue from 'vue'
import VueRouter from 'vue-router'
import Login from '../components/Login.vue'
import Home from '../components/Home.vue'
import Welcome from '../components/Welcome.vue'
import User from '../components/Users.vue'


Vue.use(VueRouter)

// const routes = []

const router = new VueRouter({
    routes: [{
        path: '/',
        redirect: '/login'
    }, {
        path: '/login',
        component: Login
    }, {
        path: '/home',
        component: Home,
        redirect: '/welcome',
        children: [
            { path: '/welcome', component: Welcome },
            { path: '/users', component: User }
        ]
    }]
});

// 挂载路由导航守卫
// to 将要访问的路径
// from 代表从哪个路径跳转而来
// next 是一个函数，表示放行
// next() 放行 next('/login') 强制跳转
router.beforeEach((to, from, next) => {
    // 如果用户访问的登录页面，直接放行
    if (to.path === '/login') return next();
    // 从sessionStorage 中获取 保存的 token 值
    const tokenStr = window.sessionStorage.getItem('token')
        // 没有token，强制跳转到登录页面
    if (!tokenStr) return next('/login');
    next();
});

export default router